Bioinspired Nanolayered Structure Tuned by Extensional Stress: A Scalable Way to High-Performance Biodegradable Polyesters.

The nacre-inspired multi-nanolayer structure offers a unique combination of advanced mechanical properties, such as strength and crack tolerance, making them highly versatile for various applications. Nevertheless, a significant challenge lies in the current fabrication methods, which is difficult to create a scalable manufacturing process with precise control of hierarchical structure. In this work, a novel strategy is presented to regulate nacre-like multi-nanolayer films with the balance mechanical properties of stiffness and toughness.

Structuring restricted amorphous molecular chains in the reinforced cellulose film by uniaxial stretching.

The construction of the preferred orientation structure by stretching is an efficient strategy to fabricate high-performance cellulose film and it is still an open issue whether crystalline structure or amorphous molecular chain is the key factor in determining the enhanced mechanical performance. Herein, uniaxial stretching with constant width followed by drying in a stretching state was carried out to cellulose hydrogels with physical and chemical double cross-linking networks, achieving high-performance regenerated cellulose films (RCFs) with an impressive tensile strength of 154.5 MPa and an elastic modulus of 5.

Hierarchically porous cellulose-based carbon aerogels with N-doped skeletons and encapsulated iron-based catalysts for efficient tetracycline catalytic degradation.

Three-dimensional interpenetrating and hierarchically porous carbon material is an efficient catalyst support in water remediation and it is still a daunting challenge to establish the relationship between hierarchically porous structure and catalytic degradation performance. Herein, a highly porous silica (SiO)/cellulose-based carbon aerogel with iron-based catalyst (FeO) was fabricated by in-situ synthesis, freeze-drying and pyrolysis, where the addition of SiO induced the hierarchically porous morphology and three-dimensional interpenetrating sheet-like network with nitrogen doping. The destruction of cellulose crystalline structure by SiO and the iron-catalyzed breakdown of glycosidic bonds synergistically facilitated the formation of electron-rich graphite-like carbon skeleton.

Nanopatterning of beaded poly(lactic acid) nanofibers for highly electroactive, breathable, UV-shielding and antibacterial protective membranes.

Despite great potential in fabrication of biodegradable protective membranes by electrospinning of poly(lactic acid) (PLA) nanofibers, it is still thwarted by smooth surfaces and poor electroactivity that challenge the promotion of electret properties and long-term air filtration performance. Here, a microwave-assisted synthetic method was used to customize dielectric TiO nanocrystals of ultrasmall and uniform dimensions (∼30 nm), which were homogeneously embedded at beaded PLA nanofibers (PLA@TiO, diameter of around 280 nm) by the combined "electrospinning-electrospray" approach. With small amounts of TiO (2, 4 and 6 wt%), the nanopatterned PLA@TiO nanofibrous membranes (NFMs) were characterized by largely increased dielectric constants (nearly 1.

Self-Charging, Breathable, and Antibacterial Poly(lactic acid) Nanofibrous Air Filters by Surface Engineering of Ultrasmall Electroactive Nanohybrids.

Despite the great promise in the development of biodegradable and ecofriendly air filters by electrospinning of poly(lactic acid) (PLA) nanofibrous membranes (NFMs), the as-electrospun PLA nanofibers are generally characterized by poor electroactivity and smooth surface, challenging the exploitation of electrostatic adsorption and physical interception that are in need for efficient removal of pathogens and particulate matters (PMs). Herein, a combined "electrospinning-electrospray" strategy was disclosed to functionalize the PLA nanofibers by direct anchoring of highly dielectric BaTiO@ZIF-8 nanohybrids (BTO@ZIF-8), conferring simultaneous promotion of surface roughness, electret properties (surface potential as high as 7.5 kV), and self-charging capability (∼190% increase in tribo-output voltage compared to that of pure PLA).

Robust, Fully Biodegradable Films of Polyesters Realized by In Situ Formation of an Interconnected Multi-Nanolayer Structure under Extensional Flow.

Multilayer structures are not only applied to manipulate properties of synthetic polymer materials such as rainbow films and barrier films but also widely discovered in natural materials like nacre. In this work, in situ formation of an interconnected multi-nanolayer (IMN) structure in poly(butylene adipate-co-terephthalate) (PBAT)/poly(butylene succinate) (PBS) cocontinuous blends is designed by an extensional flow field during a "casting-thermal stretching" process, combining the properties of two components to a large extent. Hierarchical structures including phase morphology, crystal structure, and lamellar crystals in IMN films have been revealed, which clearly identifies the crucial role of extensional flow.

Enhanced Dielectric Properties of All-Cellulose Composite Film via Modulating Hydroxymethyl Conformation and Hydrogen Bonding Network.

Cellulose-based dielectrics with attractive dielectric performance are promising candidates to develop eco-friendly electrostatic energy storage devices. Herein, all-cellulose composite films with superior dielectric constant were fabricated by manipulating the dissolution temperature of native cellulose, where we revealed the relationship among the hierarchical microstructure of the crystalline structure, the hydrogen bonding network, the relaxation behavior at a molecular level, and the dielectric performance of the cellulose film. The coexistence of cellulose I and cellulose II led to a weakened hydrogen bonding network and unstable C6 conformations.

Extensional Stress-Induced Ductility of Poly(l-lactide) Films: Role of the Entangled Network in Amorphous Regions.

The relationship between the density of the entangled amorphous network and the ductility of oriented poly(l-lactide) (PLLA) films is explored based on the preferential hydrolysis of the amorphous regions in phosphate buffer solution (PBS). PLLA films with a balance of ductility and stiffness have been prepared by the "casting-annealing stretching" based on mechanical rejuvenation, and the structural evolution and mechanical properties at different hydrolysis durations have been identified. Various stages are found during the transition of ductility to brittleness for hydrolyzed PLLA films.

Toward Excellent Energy Storage Performance via Well-Aligned and Isolated Interfaces in Multicomponent Polypropylene-Based All-Organic Polymer Dielectric Films.

Polypropylene (PP) serves as an excellent commercialized polymer dielectric film owing to its high breakdown strength, excellent self-healing ability, and flexibility. However, its low dielectric constant causes the large volume of the capacitor. Constructing multicomponent polypropylene-based all-organic polymer dielectric films is a facile strategy for achieving high energy density and efficiency simultaneously.

Flexible Polydimethylsiloxane Composite with Multi-Scale Conductive Network for Ultra-Strong Electromagnetic Interference Protection.

Highlights: A multi-scale conductive network was constructed in flexible PDMS/Ag@PLASF/CNT composite with micro-size Ag@PLASF and nano-size CNT. The PDMS/Ag@PLASF/CNT composite showed outstanding electrical conductivity of 440 S m and superior electromagnetic interference shielding effectiveness of up to 113 dB. The PDMS/Ag@PLASF/CNT composites owned good retention (> 90%) of electromagnetic interference shielding performance even after subjected to a simulated aging strategy or 10,000 bending-releasing cycles.

Reorganization of Hydrogen Bonding in Biobased Polyamide 5,13 under the Thermo-Mechanical Field: Hierarchical Microstructure Evolution and Achieving Excellent Mechanical Performance.

The hierarchical microstructure evolution of an emerging biobased odd-odd polyamide 5,13 (PA5,13) films under the thermo-mechanical field, stepping from hydrogen bond (H-bond) arrangement to the crystalline morphology, has been investigated systematically. It is found that the reorganization of H-bonds under the thermo-mechanical field plays a crucial role in the crystallization of PA5,13. Especially, it is revealed that the crystallization process under the thermo-mechanical field develops along the chain axis direction, while lamellar fragmentation occurs perpendicular to the chain axis.

The coupling effect of cellulose nanocrystal and strong shear field achieved the strength and toughness balance of Polylactide.

Up to now, unbalanced mechanical properties and poor heat resistance have become two major problems of polylactic acid (PLA). In this study, the coupling between Cellulose nanocrystal (CNC) and strong shearing field formed a unique hierarchical structure. Compared with pure PLA, the tensile strength of DPIM PLA/CNC increased from 57.

Natural cellulose supported carbon nanotubes and FeO NPs as the efficient peroxydisulfate activator for the removal of bisphenol A: An enhanced non-radical oxidation process.

Currently, many catalysts are inconvenient to separate from water, and the solvents used in the preparation process are not environmentally friendly, resulting in low recovery efficiency and secondary pollution. In this study, the magnetic and porous regenerated cellulose/carbon nanotubes/FeO nanoparticles (RC/CNTs/FeO NPs) composites were synthesized for activation of peroxydisulfate (PDS) in a green alkaline-urea system. The RC/CNTs/FeO NPs-PDS system achieved 100% removal of bisphenol A compared with CNTs (~64.

Enhanced piezoelectricity from highly polarizable oriented amorphous fractions in biaxially oriented poly(vinylidene fluoride) with pure β crystals.

Piezoelectric polymers hold great potential for various electromechanical applications, but only show low performance, with |d | < 30 pC/N. We prepare a highly piezoelectric polymer (d = -62 pC/N) based on a biaxially oriented poly(vinylidene fluoride) (BOPVDF, crystallinity = 0.52).

Durably Ductile, Transparent Polystyrene Based on Extensional Stress-Induced Rejuvenation Stabilized by Styrene-Butadiene Block Copolymer Nanofibrils.

The glassy polymer of polystyrene (PS) enjoys a good reputation as a promising optical material; however, the inherent brittleness hinders its further applications. Conventional toughening methods are realized based on the premise of a sacrifice in transparency and stiffness. In this work, we found an unprecedented strategy to address these obstacles by combining extensional stress-induced ductility and suppressing physical aging.

Hydrophobic Graphene Oxide as a Promising Barrier of Water Vapor for Regenerated Cellulose Nanocomposite Films.

Regenerated cellulose (RC) films exhibit poor water barrier performance, which seriously restricts its applications. To address this issue, an impermeable and hydrophobic graphene oxide modified by chemically grafting octadecylamine (GO-ODA) was utilized to enhance the water vapor barrier performance of RC nanocomposite films. Compared to the neat RC film, more than 20% decrease in the coefficient of water vapor permeability ( ) was achieved by loading only 2.

Interconnected Microdomain Structure of a Cross-Linked Cellulose Nanocomposite Revealed by Micro-Raman Imaging and Its Influence on Water Permeability of a Film.

Substantial adsorption of water vapor triggered by hydrogen-bonding interactions between water molecules and cellulose chains (or nanoplates) is hard to avoid in nanocomposite films, although the addition of nanoplates can improve the oxygen (or carbon dioxide) barrier property. In the present work, an effective strategy is raised to decline adsorption by weakening hydrogen-bonding interactions via chemical cross-linking by epichlorohydrin (ECH) without sacrificing the homogeneous dispersion of nanoplates. The generated microdomain structure of the chemical cross-linking reaction via ECH is explicitly revealed by micro-Raman imaging.

Constructing Sandwich-Architectured Poly(l-lactide)/High-Melting-Point Poly(l-lactide) Nonwoven Fabrics: Toward Heat-Resistant Poly(l-lactide) Barrier Biocomposites with Full Biodegradability.

Heat-resistant poly(l-lactide) (PLLA) barrier biocomposites with full biodegradability were realized through the construction of locally oriented and compact transcrystallinity supernetworks in the network of high-melting-point poly(l-lactide) (hPLLA) nonwoven fabrics composed of high-efficiency nucleating hPLLA fiber through design of two types of sandwich architectures for PLLA/hPLLA nonwoven fabrics, where single or double hPLLA nonwoven fabrics were introduced at the core or two sides of PLLA matrix film, respectively. The hPLLA fiber induced dense and oriented PLLA transcrystallinity in networks of hPLLA nonwoven fabrics and impermeable crystalline layers were formed with well-interlinked lamellae, which served as impermeable barriers to oxygen and water vapor molecules. Moreover, hPLLA nonwoven fabrics involving the compact transcrystallinity behaved as framework to support the PLLA matrix and resist the thermal deformation.

Robust cellulose nanocomposite films based on covalently cross-linked network with effective resistance to water permeability.

Cellulose films are of poor water-vapor barrier performance. Herein, we put forward an effective way to suppress adsorption by crosslinking of hydroxyl groups via epichlorohydrin (ECH), meanwhile graphene oxide (GO) nanosheets are utilized to prolong the pathway of vapor penetration. The strategy confers a significant enhancement of vapor barrier performance as well as mechanical properties to cellulose-based films.

Robustly Superhydrophobic Conductive Textile for Efficient Electromagnetic Interference Shielding.

Superhydrophobic electromagnetic interference (EMI) shielding textile (EMIST) is of great significance to the safety and long-term service of all-weather outdoor equipment. However, it is still challenging to achieve long-term durability and stability under external mechanical deformations or other harsh service conditions. Herein, by designing and implementing silver nanowire (AgNW) networks and a superhydrophobic coating onto a commercial textile, we demonstrate a highly robust superhydrophobic EMIST.

Wearable Polyethylene/Polyamide Composite Fabric for Passive Human Body Cooling.

Personal cooling technologies (PCTs) locally control the temperature of an individual instead of a whole building and are thus energy saving. However, most PCTs still consume energy and are heavy in weight, restricting their application among human beings. To achieve personal thermal comfort and no energy consumption on hot summer days, we designed a bilayer structure fabric with high thermal comfort by increasing the dissipation of human thermal radiation and reducing solar energy absorption simultaneously.

Ultralight Cellulose Porous Composites with Manipulated Porous Structure and Carbon Nanotube Distribution for Promising Electromagnetic Interference Shielding.

Lightweight conductive polymer composites based on biomass could be a promising candidate for electromagnetic interference (EMI) shielding application. Herein, tailoring porous microstructure and regulating the distribution of carbon nanotubes (CNTs) in cellulose composites are attempts to achieve highly efficient EMI shielding properties accompanying desired mechanical property and low density. Specifically, aligned porous structure is fabricated by ice-template freeze-drying method; meanwhile, CNT is regulated to decorate inside the cellulose matrix (CNT-matrix/cellulose porous composites) or to directly bind over the cellulose cell walls (CNT-interface/cellulose porous composites).

Ultra-high mechanical properties of porous composites based on regenerated cellulose and cross-linked poly(ethylene glycol).

The ultra-high mechanical, biocompatible and biodegradable porous regenerated cellulose/poly(ethylene glycol) (RC/PEG) composites with double network structure were fabricated via an simple method to dissolve cellulose followed by UV irradiation. The porous structure of RC/PEG was sensitively altered by PEG contents, which led to the porous structure morphology transition from 3D fibrillar network to close-grained sheet-like-network with the loading of cross-linked PEG. The porous RC/PEG showed excellent mechanical properties, i.